1. Field of Invention
The present invention relates to transferring a pattern of an electrical circuit from one substrate to another substrate, to a display device (electro-optical device) using this technology, and to a method of manufacturing the same.
2. Description of Related Art
In related art display devices (electro-optical devices) in which pixels are driven by thin-film transistors (TFTs), such as a TFT-driven liquid crystal display (LCD), a TFT-driven organic electroluminescent display device, a TFT-driven light-emitting diode (LED) display device, and a TFT-driven electrophoretic display device, TFTs are part of the overall device. In most cases, the remaining significant part of the device includes lines, a support substrate, etc. In manufacturing such a display device (TFT-driven display device), when TFTs, lines and a support substrate are integrally formed in the same processes, an advanced and complicated manufacturing process of producing TFTs is necessary. As a result, the manufacturing cost becomes generally high. In contrast, such an advanced and complicated manufacturing process is unnecessary to produce lines and a support substrate, and the manufacturing cost is thus low. If TFTs are produced separately from lines and a support substrate and then arranged at necessary positions, the manufacturing cost of a TFT-driven display device can be reduced.
To satisfy such a demand, a transfer method is developed including: forming a to-be-transferred layer including elements, such as TFTs, on a transfer source substrate, the to-be-transferred layer being separated from the transfer source substrate by an ablation layer; joining the transfer source substrate including these layers to a transfer destination substrate; and irradiating the ablation layer with light to cause ablation, thereby removing the transfer source substrate from the ablation layer to form elements at desired positions on the transfer destination substrate. Such a transfer method is disclosed in, for example, Japanese Unexamined Patent Application Publication No. 10-125931. Using the above-described transfer method, TFTs are arranged only at necessary positions. Averaging the cost of all the components, the overall manufacturing cost of this TFT-driven display device is reduced.